SEATTLE , WA_ Shrinking glaciers in the Cascades, and some dwindling
winter snowpacks, could ultimately mean increased winter flooding
and drier summers, further endangering fish runs and driving up the
cost of power.

Scientists say weather fluctuations, global warming and human activity
are causing some glaciers to shrink and are affecting snowpacks --
the snowdrifts that melt each spring before they can compress and
turn into glaciers.

Lessened spring runoff means less water in the rivers that produce
hydroelectric power, irrigation and drinking water and sustain the
region's salmon runs.

If the trend continues, some experts think the region may have to
considering building more dams, or choose between using river water
for power or leaving it for salmon.

Scientists estimate that South Cascade Glacier, 25 miles east of
Darrington, has shrunk 40 percent since the last severely cold period
350 years ago. The end of the glacier has retreated nearly two-thirds
of a mile since 1928, said Ed Josberger, who heads a glacier-monitoring
team for the U.S. Geological Survey in Tacoma. A lake has formed where
the toe of the glacier once reached.

The shrinkage occurred even though the region has experienced several
lengthy spells of cold weather that might have helped the glaciers
grow.

The National Park Service has begun measuring the effects on glaciers
in North Cascades National Park.

North Klawatti and Noisy glaciers, in the North Cascades, have each
lost three feet or more in their vertical mass since 1993. In each
case, the loss is considered significant; the loss at Klawatti is
equivalent to more than 10,000 Olympic-size swimming pools. Seasonal
water runoff from Klawatti Glacier supplies Diablo Lake, where the
water is used to generate hydroelectric power.

A study of Mount Rainier glaciers shows that most major glaciers
except Nisqually Glacier became smaller during an 80-year period.

Similar changes have been noticed in glaciers in Alaska, Montana,
Canada and in the Andes range in South America.

Philip Mote and others on a University of Washington team of climate
experts say global warming is a likely cause, though they differ on
how much of the warming is due to human activities such as fuel burning.

Others, like UW hydrologist Alan Hamlet, say changing weather patterns
could explain why many glaciers and snowpacks are shrinking. The region
has experienced four different phases of alternating warm-and-dry
and cool-and-wet weather since the mid-1920s.

And two of the North Cascades glaciers being monitored, Silver Glacier
and Sandalee, have grown in the past decade because the mountain peaks
shade them more than others.

Seattle, which has 1.3 million water customers, has asked the UW
team to study the possible effects of global warming on its system.
Faster melting of snow may force the release of more water from reservoirs
and cause possible downstream flooding.

Lower summer flows could mean too little water in the rivers for
fish, while water demand could rise because of higher temperatures.

Earlier melting would send more water through hydroelectric dams,
producing more power in winter when the Northwest needs it. But lower
summer flows would mean less power production when the Northwest typically
sells power to the Southwest, said Northwest Power Planning Council
analyst John Fazio. That lost revenue could prompt rate increases.